The ATI Infrared Receiver

During my training seminars several technicians expressed interest in building my infrared receiver. I use this receiver to check remotes for stuck buttons, evidence of IR output, and measuring the IR data from TV or VCR remote controls. It also comes in handy for tracking down sources of  IR interference.

Two years ago I was involved in a repair of a projection television where the remote had poor sensitivity. The remote was replaced first, then the IR receiver without correcting the symptom.   Once my special IR receiver was activated, it  immediately began giving an audible noise from an interfering source. In less than a minute the tech  found the source of the interference which was an IR. motion detector.  Disabling the motion detector allowed the TV to return to normal operation, and the remote returned to nearly 30 feet of operating distance.

I especially like this receiver because it gives me a nice audible response when checking out a universal remote control for the ability to change codes. Listen to these sounds. It is IR data from the "Channel up" command from 3 remotes.   Sony VCR ,   MGA TV, &  a  Scientific Atlantic Cable Box

For those of you who wish to build this unique receiver the following is a detailed description, parts list, and schematic covering the IR. receiver. I'm working on a circuit board for the next version of my receiver. It will use surface mounted components because it is easier to construct. Minimal drilling.

Parts List

R3= 100 ohm resistor ¼ watt                                            VR1= 10K pot
C1= 10 MFD                                                                        C2= 10 mfd
C3= 1 MFD                                                                          C4= .05 MFD
C5= 220 mfd (radial) @ 16 vdc                                         D1= 5.1 volt zenor diode
R1= 10 ohms  1/4 watt                                                        R2= 1000 ohm  1/4 watt
R3= 100 ohm 1/4 watt                                                         9 volt battery snap connector 270-325= $1.39
IC= LM386 audio amp = 276-1731 = $1.79                      SPKR= Speaker 29mm dia =2793-092 = $2.29
IR detector module = 276-137 = $3.59                             Switch SPST 275-407= $1.19
IR box RS-270-211 =$5.29

Construction is very simple. There are no special construction techniques. This unit can be built in about 1 to 2 hours on bread board.  All parts available from Radio Shack.. The IR box has the special IR band pass filter lens as part of the cabinet and a neat battery compartment too. You will need to drill holes to create a speaker grill to let the sound escape.

The following schematic is the complete IR receiver. It may take an hour or so to build and component layout is not critical. The device consumes about 15 ma of current so a rectangle 9 volt battery will do fine for powering the unit.  Click to see completed IR receiver
Theory of operation: Power from a 9 volt battery supplies the IR receiver, and IC1. A zener is used to clamp the voltage out of the IR detector module to 5 volts.  The IR receiver will output 5 volts pp signal and feed into the input of R2 where the wiper output is fed into the non inverting input of IC1. IC1's output is capacitor coupled into a small 29mm speaker. When a remote control is used to excite the IR receiver the speaker will sound a pulsing a low frequency buzzing noise that resembles the data output of the remote control.

Some of the older remote controls (pre 1981) used unmodulated carrier frequencies of 38 kHz, 41.5 Khz … etc. to control a limited number of functions.  I would guess these Televisions have long gone to that old television resting place in the sky.

Happy Listening         Dennis Viereck                       wa6ati@charter.net